The National Weather Service has finished its assessment of the damage left by Monday's devastating tornado in Newcastle and Moore, OK, just to the south of Oklahoma City. Their final conclusion is that the tornado was an EF-5, with winds of approximately 210mph at its strongest point. The picture below is the graphical assessment issued by the NWS office in Norman, OK:

The blue outline shows the total area that experienced at least EF-0 winds. The yellow line is where the damage was at least at EF-2 strength; and finally, the red line shows winds of at least EF-4 intensity. As you probably know, the old F Scale for classifying tornadoes was retired in 2007. The EF (Enhanced Fujita) Scale maxes out at EF-5, and the NWS believes that the Newcastle/Moore tornado reached this strength as it passed over Briarwood Elementary.The graphic below shows the EF Scale and the type of damage associated with each EF rating:

As you can see, with an EF-5, almost nothing is left standing. The NWS says that "well constructed homes are swept away" in an EF-5, and even "steel-reinforced concrete structures are critically damaged". When a tornado's winds exceed 200mph, the only safe place to be is underground. Tornadoes very rarely reach EF-5 status; in fact, the last EF-5 tornadoes happened during the outbreak of May 2011 that devastated Joplin, MO. But, not only did this tornado become an EF-5, it also passed directly over two elementary schools.

It was immediately obvious that the tornado that struck Moore, OK on Monday was catastrophic. The damage in the immediate aftermath was stunning; we soon learned that it was also tragic, with seven children losing their lives at Plaza Tower Elementary in this suburb of Oklahoma City.

The events that unfolded were a worst-case scenario. Under normal circumstances, a school provides better shelter from tornadoes than a residential home if the home doesn't have a basement. With no way to get underground, the people at Plaza Towers were vulnerable. If the tornado's path had been just a few blocks to the right or left, those children might be alive today. But in addition, if Plaza Tower had been equipped with a proper storm shelter underground, more lives would have been spared.

It's worth mentioning that an F-5 or EF-5 tornado has never happened in DC, Maryland or Virginia. However, F-4 and EF-4 tornadoes have touched down in Maryland, with the most recent being the LaPlata tornado in 2002. If you do not have a basement, the safest place in your home to ride out a tornado is the bathroom, because it is usually an interior room without windows, and the plumbing in the wall provides additional reinforcement to the structure. The vast majority of schools in the DC Metro area would remain standing even if an EF-3 or EF-4 tornado passed over them. We can only hope that a tragedy like this one never happens again.